SNOSDF7A May   2023  – December 2023 LM74703-Q1 , LM74704-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input Voltage
      2. 8.3.2 Charge Pump
      3. 8.3.3 Gate Driver
      4. 8.3.4 Enable
      5. 8.3.5 FET Status Indication (FETGOOD)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Conduction Mode
        1. 8.4.2.1 Regulated Conduction Mode
        2. 8.4.2.2 Full Conduction Mode
        3. 8.4.2.3 Reverse Current Protection Mode
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Design Considerations
        2. 9.2.2.2 MOSFET Selection
        3. 9.2.2.3 Charge Pump VCAP, Input and Output Capacitance
        4. 9.2.2.4 Selection of TVS Diodes for 12-V Battery Protection Applications
        5. 9.2.2.5 Selection of TVS Diodes and MOSFET for 24-V Battery Protection Applications
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

3 Description

The LM74703-Q1, LM74704-Q1 is an automotive AEC Q100 qualified ideal diode controller which operates in conjunction with an external N-channel MOSFET as an ideal diode rectifier for low-loss reverse polarity protection with a 20-mV forward voltage drop. The wide supply input range of 3.2 V to 65 V allows control of popular DC bus voltages such as 12-V, 24-V, and 48-V automotive battery systems. The 3.2-V input voltage support is designed especially for severe cold crank requirements in automotive systems. The device can withstand and protect the loads from negative supply voltages down to –65 V.

The device controls the gate of the MOSFET to regulate the forward voltage drop at 20 mV. The regulation scheme enables graceful turn off of the MOSFET during a reverse current event and provides zero DC reverse current flow. Fast response (< 0.75 µs) to reverse current blocking makes the device applicable for systems with output voltage holdup requirements during ISO7637 pulse testing as well as power fail and input micro-short conditions. LM74703-Q1, LM74704-Q1 has FETGOOD output to indicate external MOSFET drain to source short or open condition. The device features enable pin (EN). With the enable pin low, the controller is off and draws approximately 1-µA of current.

Device Information
PART NUMBER PACKAGE(1) PACKAGE SIZE(2)
LM74703-Q1 DDF (SOT-23, 8) 2.90 mm × 1.60 mm
LM74704-Q1
(1) For more information, see Section 12.
(2) The package size (length × width) is a nominal value and includes pins, where applicable.
GUID-20231126-SS0I-HSSJ-KL7B-FVKL1CCKDBGN-low.svgLM74703-Q1 Typical Application Schematic
GUID-20231126-SS0I-6JCX-CX2G-C7XPXZ15MZPD-low.svgLM74704-Q1 Typical Application Schematic